10 major characters of 8 hybrids of pop corn,including height（X₁）,diameter of ear（X₂）,ear length（X₃）,grain number per row（X₄）,bald tip length（X₅）,1000 grain weight（X₆）,grain weight per plant（X₇）,ear weight per plant（X₈）,grain rate（X₉） and Yield（Y）,were studied by use of gray correlation degree.The results indicated that ear length,1000 grain weight,ear weight per plant exhibit important effect on yield,and they should be main indexes on selection of off spring.